﻿/************************************************************************

   Extended Silverlight Toolkit

   Copyright (C) 2010-2012 Xceed Software Inc.

   This program is provided to you under the terms of the Microsoft Public
   License (Ms-PL) as published at http://extendedsilverlight.codeplex.com/license

   Please purchase a commercial version of this toolkit if you are using
   it in a commercial product. The commercial versions support the project,
   and also include more features for each control, priority support,
   source code, updates, removed watermark, and a proprietary license.

   Visit http://xceed.com and follow @datagrid on Twitter.

  **********************************************************************/

using System.Diagnostics;

namespace Xceed.Silverlight.Data
{
  public abstract class FilterExpressionVisitor
  {
    #region Constructor

    protected FilterExpressionVisitor()
    {
    }

    protected FilterExpressionVisitor( FilterExpressionBase expression )
    {
      m_expression = expression;
    }

    #endregion

    [DebuggerStepThrough]
    protected void Visit()
    {
      this.Initialize();

      FilterExpressionBase expression = this.GetFirstExpression();

      this.Visit( expression );
    }

    protected virtual void Initialize()
    {
    }

    protected virtual FilterExpressionBase GetFirstExpression()
    {
      return m_expression;
    }

    [DebuggerStepThrough]
    protected void Visit( FilterExpressionBase expression )
    {
      if( expression != null )
      {
        expression.Accept( this );
      }
    }

    protected internal abstract void Visit( FilterExpression expression );

    protected internal abstract void Visit( AndFilterExpression expression );

    protected internal abstract void Visit( OrFilterExpression expression );

    protected internal abstract void Visit( NotFilterExpression expression );

    #region Private Fields

    private FilterExpressionBase m_expression;

    #endregion
  }
}
